Method for transmission and reception of ultrasonic beams using ultrasonic transducer element array

Abstract

Disclosed is a method for transmission and reception of ultrasonic beams using an array of ultrasonic transducer elements in which a plurality of transducer element sets each including the selected number of transducer elements for the transmission and/or reception of ultrasonic beams are sequentially selected. First and second sets having different focal axes defined relative to the plane of the transducer array are selected for the transmission and reception modes of operation respectively during the production of a single scan line. The position of at least one of the transducer elements in the first set is different from those of the transducer elements in the second set.

We claim: 
     
       1. A method for transmission and reception of ultrasonic beams using a linear array of plural ultrasonic transducer elements, focal axes of transmitted ultrasonic beams being respectively defined relative to the planes of transducer element sets each of which includes a selected number of ultrasonic transducer elements, said method during the production of a single scan line comprising: a step of simultaneously exciting the transducer elements of a first transducer element set to transmit ultrasonic beams from the transducer elements of said first transducer element set to a point on a first focal axis defined by said first transducer element set; and   a step of receiving said ultrasonic beams transmitted from said first transducer element set and reflected from an object by the transducer elements of a second transducer element set which defines a second focal axis different in position relative to the plane of the array than said first focal axis.   
     
     
       2. A method according to claim 1, wherein the number of transducer elements constituting said first set is different from that of transducer elements constituting said second set. 
     
     
       3. A method according to claim 1, wherein the number of transducer elements constituting said first set is the same as that of transducer elements constituting said second set, and the position of at least one of the transducer elements constituting said first set is different from those of the transducer elements constituting said second set. 
     
     
       4. In a method for transmission and reception of ultrasonic beams comprising a step of transmitting ultrasonic beams from an array of plural ultrasonic transducer elements arranged on a line and a step of receiving the ultrasonic beams by the transducer array, thereby to produce a plurality of scan lines, the improvement in that the production of a single scan line includes the step of simultaneously transmitting ultrasonic beams from a first set of transducer elements in the transducer array along a first focal axis to an object and the step of simultaneously receiving, the ultrasonic beams transmitted from said first set of transducer elements and reflected from said object, by a second set of transducer elements in the transducer array, said second set having a focal axis defined relative to the plane of the array which differs from the focal axis of said first set.   
     
     
       5. A method according to claim 4, wherein the second set includes part of the transducer elements of the first set and at least one transducer element other than the transducer elements of the first set. 
     
     
       6. A method according to claim 4, wherein said array is linear. 
     
     
       7. In a method for transmission and reception of ultrasonic beams comprising a step of transmitting ultrasonic beams from an array of plural ultrasonic transducer elements arranged on a line and a step of receiving the ultrasonic beams by the transducer array, thereby to produce a plurality of scan lines, the improvement in that the production of successive single scan lines includes the step of simultaneously transmitting ultrasonic beams from a first set of transducer elements in the transducer array to an object, the step of simultaneously receiving, the ultrasonic beams transmitted from said first set of transducer elements and reflected from said object, by said first set of transducer elements in the transducer array to produce a first single scan line, the step of again simultaneously transmitting ultrasonic beams from said first set of transducer elements to said object, and the step of simultaneously receiving, the ultrasonic beams transmitted from said first set of transducer elements and reflected from said object, by transducer elements of a second set of transducer elements different from said first set of transducer elements to produce the next single scan line.   
     
     
       8. A method according to claim 7, wherein a combined directivity characteristic of the transmission and reception beams moves an increment along the line on which the transducer elements are arranged which increment is equal to d/4, where d equals the pitch provided between each adjacent transducer element. 
     
     
       9. A method according to claim 7, wherein the second set of transducer elements has a focal axis defined relative to the plane of the array which differs from the focal axis of the first set of transducer elements defined relative to the plane of the array. 
     
     
       10. A method according to claim 7, wherein said array is linear. 
     
     
       11. A method according to claim 7, wherein after reception on said second set of transducers the method further comprises the step of again simultaneously transmitting ultrasonic beams from said first set of transducers to said object, the step of simultaneously receiving the ultrasonic beams transmitted from the first set of transducer elements and reflected from said object by transducer elements of a third set of transducer elements different from said first and said second set of transducer elements to produce the next successive single scan line, the step of simultaneously transmitting ultrasonic beams from said second set of transducer elements in the transducer array to said object, the step of simultaneously receiving ultrasonic beams transmitted from said second set of transducer elements and reflected from said object by transducer elements of said third set of transducer elements to produce the next successive single scan line, the step of again simultaneously transmitting ultrasonic beams from said second set of transducer elements in the transducer array to said object, and the step of simultaneously receiving ultrasonic beams transmitted from said second set of transducer elements in the transducer array and reflected from said object, whereby the combined directivity characteristic of the transmission and reception beams moves in increments along the line on which the transducer elements are arranged which increments are equal to d/4, where d equals the pitch provided between each adjacent transducer element.